The present invention relates to a charging circuit for an electrical energy storage device, a drive system having a charging circuit, and a method for operating a charging circuit.
Motor vehicles that are completely or at least in part electrically driven such as for example hybrid vehicles and electric vehicles are becoming increasingly more important. The desire for greater driving ranges and capacities of the electrically driven vehicles is also increasing simultaneously. The charging technology for electric vehicles is also becoming increasingly more important in this connection. Present-day electric vehicles typically use conductive charging concepts that represent units that are self-sufficient and spatially separate from the electronic drive system. Furthermore, charging concepts that function in a contact-less and generally inductive manner are also already known. These charging concepts are typically likewise embodied as stand-alone systems.
The European patent application EP 0 768 774 A2 discloses a device for charging batteries in electric vehicles. The electric vehicle comprises an electronic regulation system that has a recovery facility. A DC current source provides a direct current that charges the battery by way of this electronic regulation system so as to charge the battery.
Owing to the increasing battery capacities and the endeavors to achieve ever-reducing charging time periods, it is desirable that the magnitude of energy that is transferred per unit of time in the charging operation is approximately equal to the magnitude of energy that is drawn off from the traction battery during the driving operation or is even greater than the magnitude of said drawn-off energy. This requires that the components that participate in the charging procedure are embodied to cope with the high currents. The electrical energy storage device in an electric vehicle is generally charged by means of the electrical energy that is provided by means of an alternating current supply.
There is therefore a requirement for a cost-effective and efficient charging circuit for an electrical energy storage device for charging the electrical energy storage device from an AC voltage supply.